Abstract: To meet the Heijunka manufacturing requirement of multi-varieties and small batch, electronic enterprises have to cut down the changeover time of key universal equipment such as the surface mounting technology (SMT) equipment. The shorter changeover time benefits production of multi-varieties within certain period. One quick changeover method based on critical path method and time tree method is proposed to improve the changeover process. The critical path method is applied to describe the changeover process and find out the critical path. After that, changeover activities on the critical path are improved by time tree method. The time tree method is utilized to label the time and staff of each activity and distinguish inner and external changeover activities to shorten the inner changeover time. Finally, the SMT equipment of an electronic enterprise is studied. The changeover time is shortened by 58%, which benefits the achievement of Heijunka.